I have never looked into any other possibilities after being diagnosed with Grover's at a dermatologist's office years ago when I first broke out. Oddly enough, he said to me, "I know exactly what that is because I have it myself!"
Thanks for the suggestions. I have an appointment with my primary care doc in a few weeks and I will ask her for a referral to a dermatologist to see if further testing can be done. Stay well!